Career foreign service officer Morton I. Abramowitz yesterday was named the State Department's director of intelligence in what some conservatives fear is the start of a drive by Secretary George P. Shultz to purge the department of its more ideological political appointees.

Department sources revealed last week that Shultz was planning extensive shifts of ambassadors abroad and policy makers here at the assistant secretary level. Conservatives quickly discerned in this an effort by Shultz and career aides to dump some of the more zealous among the department's appointees.

The conservatives, who voiced their fears privately to the White House staff, were especially fearful that Shultz had targeted for removal four political appointees with assistant secretary rank.

One, Hugh Montgomery, a former Central Intelligence Agency employee, is the official to be replaced by Abramowitz as head of the bureau of intelligence and research.

The other three, whose status remains uncertain, are Richard T. McCormack, assistant secretary for economic affairs and a former aide to Sen. Jesse Helms (R-N.C.); Gregory J. Newell, assistant secretary for international organization affairs and a former White House assistant, and James L. Malone, assistant secretary for oceans and international environmental and scientific affairs.

The purge charges were denied by department spokesman John Hughes. He refused to discuss the status of specific officials, but said:

"The primary criterion the secretary has utilized is getting the best possible people to carry out the implementation of the president's foreign policy regardless of where they come from, and he will do that."

Hughes also said that "in the recommendations made there is no change at the assistant secretary level in the present career versus noncareer ratio. As for presidential appointees, obviously the secretary makes recommendations to the president. Those recommendations are fully discussed in the White House and the president makes the ultimate decision on presidential appointments."

Despite the denials, several administration officials outside the department said yesterday that they believe that as President Reagan prepares to begin his second term next month, Shultz is maneuvering to gain control over the foreign policy machinery by putting career foreign service officers responsive to his control in those positions most able to influence policy decisions.

One conservative official who declined to be identified said Shultz "seems to be trying to deinstitutionalize the policy machinery by getting away from the interagency method of making decisions and to personalize it by arranging things so that decisions will be made on an informal, personal contact basis between him and like-minded White House moderates such as chief of staff James A. Baker III and deputy chief of staff Michael K. Deaver."

This official expressed concern that the probable departure from White House policy councils of such hard-liners as U.N. Ambassador Jeane J. Kirkpatrick and counselor Edwin Meese III will make it more difficult for those conservatives who remain, such as Defense Secretary Caspar W. Weinberger and CIA Director William J. Casey, to influence the process.

Fueling the conservative anxiety was an article published last week by syndicated columnist Joseph Kraft.

It said that Shultz intended to control foreign policy with "professionals in the State Department -- not superstars from outside," and, in detailing Shultz's preferences, specifically mentioned McCormack, Newell and Montgomery as those on the assistant secretary level who are "good bets to be leaving soon."

In response, a State Department senior official said yesterday, "It certainly is true that George Shultz intends to be in command of his personnel situation and has obtained the president's approval for that."

But, he said that the impending shifts are being made, not out of ideological considerations, but for a number of other reasons, including competence and, in the case of ambassadorial changes, the need to rotate people who have been in place for a considerable time or who have requested changes of assignment.

He and other department officials, who asked not to be identified, said it is well known in the department that Shultz has been unhappy with the job performances of McCormack and Malone.

These officials said they were less certain about Newell's status. They noted that he is given generally good marks in the department for his handling of the U.S. decision to leave the United Nations Educational, Scientific and Cultural Organization, and one said, "There is no clear sense here that the secretary is dissatisfied with Newell."

White House officials acknowledged that the situation has caused grumbling among conservatives and complaints from some of those who fear that their jobs are in jeopardy. But they added that the matter has not become a major issue and expressed doubt that it is likely to reach proportions where Reagan, who believes in delegating substantial authority to his key Cabinet officers, is forced to intervene.

Less clear is whether congressional conservatives, such as Helms, who already are suspicious of the career foreign service and of Shultz's policies, will attempt to use their voice in the confirmation process to force the secretary into making some compromise gestures. They could do that by impeding and voting against confirmation of those whom Shultz wants in key posts.

Hughes said that Montgomery is "going to continue in government service," but he gave no details. Abramowitz's appointment is not subject to Senate confirmation.